Wire Construction Research Articles

Interaction-enabled fractonic higher-order topological phases

In this work, we present a collection of three-dimensional higher-order symmetry protected topological phases (HOSPTs) with gapless hinge modes that exist only in strongly interacting systems subject to subsystem symmetry constraints. We use a coupled wire construction to generate three families of microscopic lattice models: insulators with helical hinge modes, superconductors with chiral Majorana hinge modes, and fractionalized insulators with helical hinge modes that carry fractional charge. In particular, these HOSPTs do not require spatial symmetry protection, but are instead protected by subsystem symmetries, and support "fractonic" quasiparticle excitations that move within only a low-dimensional sub-manifold of the system. We analyze the anomaly structure for the boundary theory and the entanglement Hamiltonian, and show that the side surfaces of these HOSPTs, despite being partially gapped, exhibit symmetry anomalies, and can only be realized as the boundary of three-dimensional HOSPT phases.

A Versatile Simulation-Assisted Layered Mesh Analysis for Generalized Litz Wire Performance

This article introduces a semi-analytical method of predicting ac loss in commercial Litz wires. Simple finite-element simulations are used to compute the resultant proximity fields in a coil system of arbitrary geometry. The approach addresses non-ideal Litz wire construction by applying a surrogate skin effect model to inform and distribute the current over the cross Section into segmented layers. This simplifies the finite-element problem into a 2-D, dc simulation with a low number of mesh elements. Analytical solutions are then used to compute frequency-dependent loss due to skin and proximity effect. The method is demonstrated using two 14 American Wire Gauge (AWG) equivalent Litz wires with very different constructions and is validated with experimental results from several coil configurations. Finally, an appeal is made to commercial Litz wire manufacturers to provide an empirical “fabrication factor” specification that would allow consumers to predict the performance of a conductor in their application.

Effectiveness of wire netting fences to prevent animal access to road infrastructures: an experimental study on small mammals and amphibians

Transport infrastructures, such as highways, disrupt animal migrations and cause roadkill. To mitigate the latter problem, fences have been built but their effectiveness has rarely been tested under controlled conditions. Here, we tested the effectiveness of the most commonly used fence in France and probably in Europe (wire netting fence) to block animals. We tested the wire netting fence, with and without a structural modification (i.e. an overhang), with three small mammalian species (the European hamster: Cricetus cricetus Linnaeus, 1758; the common vole: Microtus arvalis Pallas, 1778 & the wood mouse: Apodemus sylvaticus Linnaeus, 1758) and two amphibian species (the marsh frog: Pelophylax ridibundus Pallas, 1771 & the European green toad: Bufotes viridis Laurenti, 1768). During testing, all small vertebrate species tested were placed into an arena, from which they could only escape by crossing the wire netting fence. Without an overhang, almost all adult individuals of all tested species were able to climb over a 30 to 40 cm high wire netting fence. Furthermore, the addition of an 8 cm long overhang at the top of the fence stopped the amphibian species tested but not the most agile mammalian species, such as the hamster and the wood mouse. Based on these results, we do not support the construction of wire netting fences along roads as a measure to stop small animals from crossing. We recommend the use of more effective and durable fences, which, in addition, can be associated with wildlife passages to reconnect isolated populations.

Cost Assessment of Plating Versus Tension Band Wiring Constructs for Treating Mayo Type 2A Olecranon Fractures

Tension band wiring (TBW) or plating may be used for fixation with similar clinical outcomes for adults with displaced Mayo 2A olecranon fractures. The primary hypothesis is that total direct costs (TDCs) for surgery are lower for TBW than plating. Our secondary hypothesis is that combined surgical TDCs are lower for TBW even with a 100% rate of subsequent tension band hardware removal and a 0% rate of plate removal. Patients who underwent TBW or plating of an isolated unilateral Mayo 2A olecranon fracture between July 2011 and January 2020 at a single academic medical center were identified. Then, TDC for each surgery on plate fixation, TBW, and hardware removal was obtained and converted to 2020 US dollars using information technology cost tools provided by our institution. Finally, relative TDCs were compared between plate fixation and TBW groups using univariate and multivariable generalized estimating equations with log-link. Of the 97 included patients, the mean age was 50 ± 21 years, and 48% were female. Tension band wiring and plate fixation were performed on 18% (17/97) and 82% (80/97) of male and female patients, respectively. Demographics were similar between groups, although the finding that plate fixation cost 2.6 times that of TBW within the index surgery was significant in the multivariable model, independent of potential confounders (coefficient 2.55, 95% confidence interval: 2.09-3.10). Additionally, mean TDC remained significantly greater for plate fixation even under the hypothetical situation where 100% TBW were removed, and the plate removal rate was 0% (cost difference 181%). Using TBW relative to plate fixation may improve the cost of care for operative Mayo 2A olecranon fractures. Furthermore, this finding was robust to the rate of hardware removal. Economic and Decision Analyses III.

Construction of cluster-based supramolecular wire and rectangle.

Reactions of [Et4N][Tp*WS3(CuCl)3] (1) (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) with 2 equiv. of AgOTf (OTf- = trifluoromethanesulfonate) and 1 equiv. of several bidentate pyridine ligands including 2,5-bis(pyridine-4-yl)thiazolo[5,4-d]thiazole (L1), 2,7-di(pyridin-4-yl)-9H-fluorene (L2), 2,7-di(pyridin-4-yl)-9H-carbazole (L3), and 2,7-di(pyridin-4-yl)-9H-fluoren-9-one (L4) afforded four W/Cu/S cluster-based supramolecular compounds [(Tp*WS3Cu2Cl)2(L1)] (2), {[(Tp*WS3Cu3)2(μ-Cl)2(μ4-Cl)]2(L2)2}(OTf)2 (3), {[(Tp*WS3Cu3)2(μ-Cl)2(μ4-Cl)]2(L3)2}(OTf)2 (4) and {[(Tp*WS3Cu3)2(μ-Cl)2(μ4-Cl)]2(L4)2}(OTf)2 (5). Compounds 2-5 were characterized by elemental analysis, IR, UV-vis, 1H NMR, and single-crystal X-ray diffraction analysis. The neutral cluster 2 behaves as a supramolecular wire constructed by L1 bridging two butterfly-shaped [Tp*WS3Cu2Cl] cores. The cluster cations of 3-5 contain two [(Tp*WS3Cu3)2(μ-Cl)2(μ4-Cl)]+ cores linked by two L2, L3, or L4 ligands, which finally formed a cationic supramolecular rectangle. The third-order nonlinear-optical (NLO) properties of 3-5 in DMF were also investigated by Z-scan techniques and their NLO responses were enhanced compared to those of their precursor 1.

Parallel K-Wire Placement Leads to Fusion and Midcarpal Settling in Scaphoid Excision Four-Corner Fusion.

Scaphoid excision 4-corner fusion is a motion-sparing procedure in patients with advanced radioscaphoid arthritis. This study introduces an alternate technique for scaphoid excision 4-corner fusion using a parallel Kirschner wire (K-wire) construct across the midcarpal joints that leads to reliable fusion rates, and good patient outcomes. This is a single-surgeon, retrospective study of patients who underwent scaphoid excision 4-corner fusion, using a parallel K-wire construct across the midcarpal joints. Once fusion was achieved, K-wires were removed. Radiographic union rate, time to union, capitolunate angle, capitolunate coverage, and amount of midcarpal settling are measured. Patient-reported outcome measures and descriptive statistics are presented. Sixty-five wrists were included in this study with a mean age of 50.1 years. One patient was lost to follow-up. All 64 wrists (100%) fused at an average of 2.6 months. The mean capitolunate angle was 7°, and capitolunate coverage was 99.2%. Fifty-two patients (81%) had adequate radiographs for measurement. Average midcarpal settling was 1.1 mm. Thirty-two patients (51%) were available for long-term follow-up at an average of 5.3 years (0.7-10.2 years), and participated in patient reported outcomes (PRO) surveys. The mean Quick Disabilities of the Arm, Shoulder, and Hand score was 16.6, and numeric pain rating scale score was 1.8. Parallel K-wire placement across the midcarpal joints with scaphoid leads to a high rate of fusion with good patient outcomes long term. Midcarpal settling that occurs through dynamic compression around the K-wires may have contributed to bony fusion. This technique may provide an alternative approach to achieving reliable fusion across the midcarpal joints.

Hybrid versus total sublaminar wires in patients with spinal muscular atrophy undergoing scoliosis surgery

BackgroundEarly versions of spinal muscular atrophy (SMA) scoliosis correction surgery often involved sublaminar devices. Recently, the utilization of pedicle screws has gained much popularity. Pedicle screws are generally believed to provide additional deformity correction, but pedicle size and rotational deformity limit their application in the thoracic spine, resulting in a hybrid construct involving pedicle screws and sublaminar wire. Studies of the efficacy of hybrid instrumentation in SMA scoliosis are often limited by the scarcity of the disease itself. In this study, we aimed to compare the surgical outcomes between hybrid constructs involving pedicle screws and sublaminar wire and sublaminar wire alone in patients with SMA scoliosis.MethodsWe retrospectively reviewed the clinical records and radiographic assessments of patients with SMA scoliosis who underwent corrective surgery between 1993 and 2017. The radiographic assessments included deformity correction and progressive changes in the major curve angle, pelvic tilt (PT) and coronal balance (CB). The correction of deformities was observed postoperatively and at the patient’s 2-year follow-up to test the efficacy of each type of construct.ResultsThirty-three patients were included in this study. There were 14 and 19 patients in the wiring and hybrid construct groups, respectively. The hybrid construct group demonstrated a higher major curve angle correction (50.5° ± 11.2° vs. 36.4° ± 8.4°, p < 0.001), a higher apical vertebral rotation correction (10.6° ± 3.9° vs. 4.8° ± 2.6°, p < 0.001), and a reduced progression of the major curve angle at the 2-year follow-up (5.1° ± 2.9° vs. 8.7° ± 4.8°, p < 0.001). A moderate correlation was observed between the magnitude of correction of the apical vertebral rotation angle and the major curve (r = 0.528, p = 0.002).ConclusionThis study demonstrated that hybrid instrumentation can provide a greater magnitude of correction in major curve and apical rotation as well as less major curve progression than sublaminar wire instrumentation alone in patients with SMA scoliosis. Level of evidence III

Is Nice knot suture comparable to wire for cerclage fixation? A biomechanical performance study

Cerclage fixation is a known orthopedic technique shown to be beneficial for circumferential augmentation when screw fixation cannot be used or is undesirable. However, ongoing advances in suture materials and knot techniques exist, and there is a paucity of evidence existing which evaluates comparisons between the two. The objective of this study was to investigate the strength and durability of cerclage fixation between the Nice knot suture technique and monofilament wire. Static displacement over time and compression load testing were analyzed. Compression testing was conducted with the Jamar Hydraulic Hand Dynamometer. Distraction testing was conducted using the Instron test system with its associated program. The Nice knot was tied using number 2 and number 5 FiberWire (Arthrex) and compared to monofilament wire. Clinical failure (displacement of 10 mm), absolute failure (opening of the knot or material failure), maximum compression achieved, and steady state compression maintained were the outcomes of interest. Double-stranded monofilament wire produces maximum consistent compression of 90 kg, followed by single-stranded monofilament wire (60 kg). Number 5 FiberWire has a higher maximum compression load than number 2 FiberWire (50 kg vs. 22 kg), but it is lower than that of the double-stranded monofilament wire constructs. When compared to the single-stranded monofilament construct, the number 5 FiberWire Nice knot is comparable (P < .05). Average steady state compression achieved after 10 minutes of resting showed double-stranded monofilament wire to be 65 kg compared to single- stranded monofilament wire at 42 kg, which when, compared to suture, number 5 FiberWire measured at 15 kg and number 2 FiberWire at 8 kg. Average tension results from Instron distraction testing showed the double-stranded monofilament wire construct was able to withstand greater forces up to a displacement of 6 mm, after which the number 5 FiberWire Nice knot was stiffer. Number 5 FiberWire shows the most linear tension relationship, revealing it more efficiently withstands elastic forces. Load to failure was higher in the number 5 FiberWire Nice knot construct than that in both the monofilament wire constructs. The modes of failure for the Nice knot were always at the knot suture interface rather than at the knot. We propose this suture technique to be a viable alternative method for cerclaging to fix upper limb long-bone fractures.

Fractonic topological phases from coupled wires

In three dimensions, gapped phases can support "fractonic" quasiparticle excitations, which are either completely immobile or can only move within a low-dimensional submanifold, a peculiar topological phenomenon going beyond the conventional framework of topological quantum field theory. In this work we explore fractonic topological phases using three-dimensional coupled wire constructions, which have proven to be a successful tool to realize and characterize topological phases in two dimensions. We find that both gapped and gapless phases with fractonic excitations can emerge from the models. In the gapped case, we argue that fractonic excitations are mobile along the wire direction, but their mobility in the transverse plane is generally reduced. We show that the excitations in general have infinite-order fusion structure, distinct from previously known gapped fracton models. Like the 2D coupled wire constructions, many models exhibit gapless (or even chiral) surface states, which can be described by infinite-component Luttinger liquids. However, the universality class of the surface theory strongly depends on the surface orientation, thus revealing a new type of bulk-boundary correspondence unique to fracton phases.

Simulation and fabrication of carbon nanotube–nanoparticle interconnected structures

Abstract. With the rapid development of nanotechnology, the size of a device reaches sub-nanometer scale. The larger resistivity of interconnect leads to serious overheating of integrated circuits. Silicon-based electronic devices have also reached the physical limits of their development. The use of carbon nanotubes instead of traditional wires has become a new solution for connecting nano-structures. Nanocluster particles serving as brazing material play an important role in stabilizing the connection of carbon nanotubes, which places higher demands for nanoscale manipulation techniques. In this paper, the dynamic processes under different operating scenarios were simulated and analyzed, including probe propulsion nanoparticle operation, probe pickup nanoparticle operation and probe pickup nanocluster particle operation. Then, the SEM (Scanning Electron Microscope) was used for nanoparticle manipulation experiments. The smallest unit of carbon nanotube wire was obtained by three-dimensional (3D) construction of a carbon nanotube–silver nanocluster particle (CN-AgNP), which verified the feasibility of 3D manipulation of carbon nanotube wire construction. The experiments on the construction of carbon nanotube–nanocluster particle structures in three-dimensional operation were completed, and the smallest unit of carbon nanotube wire was constructed. This nano-fabrication technology will provide an efficient and mature technical means in the field of nano-interconnection.

Biomechanical Analysis of Crossed Pinning Construct in Supracondylar Fracture of Humerus: Does the Point of Crossing Matter?

IntroductionThis appears to be the first biomechanical study that compares the stability of various locations of the crossing points in crossed pinning Kirschner wiring (K-wire) construct in treating pediatric supracondylar humerus fracture (SCHF). Additionally, this study compared the biomechanical stability between crossed pinning K-wire construct and the three-lateral divergent K-wire construct.MethodsFor the study purpose, 30 synthetic humerus bones were osteotomised at mid-olecranon fossa, anatomically reduced, and pinned using two 1.6-millimeter K-wires in five different constructs. A total of six samples were prepared for each construct and tested for extension, flexion, valgus, varus, internal rotation, and external rotation forces.ResultsAs for crossed pinning K-wire construct, the center crossing point emerged as the stiffest construct in both linear and rotational forces, in comparison to the lateral crossing point, superior crossing, and medial crossing pointConclusionBased on this analysis, it is highly recommended that, if the crossed pinning construct is selected to treat supracondylar humerus fracture, the surgeon should aim for center crossing point as it is the most stable construct. Nevertheless, if lateral and superior crossing points are obtained during the initial attempt of fixation, the fixation may be accepted without revising the K-wire as the stability of these two constructs are comparable and portrayed no significant difference when compared to that of the center crossing point. Additionally, it is essential to avoid the medial crossing point as it is significantly less stable in terms of rotational force when compared to the center crossing point.

Scapulothoracic fusion using nonabsorbable suture fixation: surgical technique and review of the literature

Historically, scapulothoracic fusion (STF) is performed using steel wire and plate construct fixation. The purpose of this study is to report a recent fusion achieved through ultra-high-molecular-weight polyethylene-reinforced suture fixation as well as to perform a systematic literature review of techniques, fusion rates, complications, and reoperation. Patient data were gathered from chart review and clinical encounters. For the review, MEDLINE, Embase, and Ovid databases were queried for STF cases. Thirty articles reporting on 386 fusion procedures were included. Including this patient, 5 of 387 (1.3%) STFs have been attempted with fiber suture. Fusion rates of metal-only constructs is 90.8% (346 of 381) with 11.3% (43 of 381) requiring wire removal or trimming because of symptomatic hardware and 7% (27 of 381) causing a postoperative pneumothorax. Although a small sample size, all fiber-suture constructs have achieved union without implant removal and without pneumothorax development. In this patient, fusion was determined radiographically at 6 months with substantial improvement in pain level and function. Scapulothoracic fusion has benefit to patients to have failed other management options for winged scapula, most commonly those with neurologic trauma or facioscapulohumeral muscular dystrophy. With advancements in surgical options, fiber-suture offers an alternative to steel wire to achieve fusion. Further cases with longer term follow-up are needed to determine if significant differences in outcomes exist between constructs.

Coupled wire construction of a topological phase with chiral tricritical Ising edge modes

Tricritical Ising (TCI) phase transition is known to occur in several interacting spin and Majorana fermion models and is described in terms of a supersymmetric conformal field theory (CFT) with central charge $c=7/10$. The field content of this CFT is highly nontrivial and includes among its primary fields the Fibonacci anyon, making it of potential interest to strategies seeking to implement fault-tolerant topological quantum computation with non-Abelian phases of matter. In this paper we explore the possibility that a TCI CFT can occur at the edge of a gapped two-dimensional topological state as a stable phase. We discuss a possible realization of this 2D phase based on a coupled-wire construction using the Grover-Sheng-Vishwanath chain model of Majorana zero modes coupled to Ising spins which is known to undergo the TCI phase transition. From the combined analysis using mean-field theory, conformal field theory and density matrix renormalization group (DMRG) on 2- and 4-leg ladders, we find that the left- and right-moving gapless TCI modes become spatially separated and reside on two opposite edges of the system, forming a precursor of the required 2D topological phase.

Management of slipped capital femoral epiphysis: Results of a survey of the members of the Paediatric Orthopaedic Society of India (POSI)

AimTo determine the preferred practices in the treatment of slipped capital femoral epiphysis (SCFE) among members of the Paediatric Orthopaedic Society of India (POSI). Materials and MethodsA questionnaire with 16 vignettes was made about SCFE and sent to all members of the Paediatric Orthopaedic Society of India (POSI) to study the similarity and variation in the management of SCFE. Specifically, respondents were asked about the role of reduction, methods of fixation, prophylactic fixation of the non-affected hip, postoperative management and their view on the prevalence of Femoro Acetabular Impingement (FAI) and anticipated need for secondary surgery. ResultsThe response rate was 94 out of 203 members of Paediatric Orthopaedic Surgeons of India (51.9%). 62 out of 94 (66%) participating surgeons had an exclusive paediatric orthopaedics workload, with 61 surgeons (65%) having more than ten years of experience. Seventy-eight surgeons (83%) were most consistent in their advice for the management of stable slips based on severity. For severe stable slips, 67 surgeons (71%) recommended Modified Dunn procedure. Around 23% of the respondents preferred to do modified Dunn’s procedure for all unstable slips while the rest had different approaches to treat this. Single Partially threaded cancellous screw is the preferred implant for in-situ fixation, while a single screw and K wire construct is the preferred construct for in Modified Dunn’s procedure. Only 17(16%) of the responders do prophylactic pinning of the opposite hip regularly. Almost 90 responders (96%) do counsel parents about FAI in later stages of life. ConclusionOur study documents that about 70% of the practising paediatric orthopaedic surgeons prefer to do capital realignment procedure for severe stable slips. The treatment of unstable slips remains controversial without any consensus though about 70% believe that there is a role of gentle reduction or positional reduction or skeletal traction. About 50% of the respondents treat less than five slips a year and thus would not possible to generate high-quality evidence based on meagre numbers. This clearly shows that there is a need for developing a national SCFE registry to pool in all data which would help us to arrive at meaningful conclusions to arrive at the ideal management guidelines for SCFE.

Combined instability assessment and rockfall hazard in volcanic rocks (Keçiören, Ankara)

Discontinuity bearing rock masses might be subjected to various mass movements due to the steep slopes, alteration, and manmade operational activities. Rockfall will take place in case several discontinuities form prismatic blocks. Special care must be taken in order to determine the rockfall potential and offer precautions. This study deals with the instabilities and rockfall hazard in an abandoned quarry, located in the residential area of Kecioren town, Ankara. This region has been declared as “Rockfall Hazardous,” threatening nearby structures. Several rockfall events have been reported, and a huge wedge-shaped block has been released from the slope in the early 2000s. The whole slope has 660 m length and with an average height of 35 m. Eocene-aged dacite is the main rock unit. The whole slope was divided into sections, concerning slope instabilities and discontinuity characterization in order to delineate the Slope Mass Rating (SMR) classes. The rockfall hazard assessment along the slope was performed including the SMR classes, topography, and 2D rockfall analyses. Based on the evaluations, a combined mapping of the slope was conducted to offer mitigation methods. The methods included the removal of blocks from the slope face, covering the slope with anchored steel wire mesh and construction of an earth wall to prevent the possible rockfall damage to residents.

Craniovertebral junction fixation in children less than 5years.

Whilst rigid fixation for craniovertebral instability is the gold standard, in very young, small children conventional management may have to be modified. We present a single-centre experience of craniocervical fixation in children under 5years. A retrospective review of cases that had undergone atlantoaxial (AA) or occipitocervical (OC) fixation aged under 5years. Fusion was assessed using computerised tomography or flexion extension X-rays. Twenty-six children (median age 2.3, range 0.8-4.9years, 19 under the age of 3) underwent OC (n = 19) or AA (n = 7) fusion between 1999 and 2016. Pathology comprised 17 congenital, five trauma, two tumour and two post-infection cases. Twenty-one patients underwent sublaminar cable fixation with calvarial, autologous bone graft and halo-body orthosis immobilisation. An occipital plate and rods to sublaminar wire construct were used in four cases. A rigid instrumented fixation with occipital plate and C2 pedicle screws was utilised in one case. Follow-up was for a median of 2.8years (range 0.03-16.3years). Initial fusion rate was 91%, reaching 100% following two re-operations. Ninety-two per cent of patients were neurologically stable or improved following surgery. Twenty-one patients had a good overall outcome. Two patients had post-operative neurological deteriorations, and four died due to non-procedure related causes. Pin site morbidity secondary to halo use occurred in five cases. High fusion rates with good outcomes are achievable using semi-rigid fixation in the under 5-year-olds. Full thickness, autologous calvarial bone graft secured with wire cables and halo external orthosis offers a safe and effective alternative technique when traditional screw instrumentation is not feasible. These slides can be retrieved under Electronic Supplementary Material.

Bilateral scapulothoracic arthrodesis for facioscapulohumeral muscular dystrophy: function, fusion, and respiratory consequences

Scapulothoracic arthrodesis (STA) has been proposed for the treatment of painful scapular winging in patients with facioscapulohumeral muscular dystrophy (FSHD). However, the rate of osseous fusion is variable, and there is a theoretical risk of reduced respiratory function after bilateral STA. This was a retrospective study of 10 STAs, performed sequentially, in 5 FSHD patients. The surgical technique involved use of a semitubular plate and wire construct with autograft (iliac crest) interposed between the scapula and rib cage. Osseous fusion, respiratory function, and shoulder function were evaluated. The mean follow-up period was 141 ± 67 months (range, 24-225 months). Early complications included 1 pneumothorax and 1 pleural effusion. No late complications occurred, and no patients underwent reoperation. On postoperative computed tomography images, complete bony union of the scapula to the ribs was observed in 90%of shoulders (9 of 10). Comparison of preoperative and postoperative pulmonary function test results showed no significant difference in vital capacity (from 87% ± 14% to 85% ± 12%) and forced vital capacity (from 86% ± 16% to 77% ± 15%). Patients gained on average 40° of active forward elevation (from 62° ± 20° to 102° ± 4°) and 22° of abduction (from 58° ± 21° to 89° ± 7°) (P < .001). The mean Subjective Shoulder Value increased from 25% ± 8% to 72% ± 18% (P < .001). All patients were pleased with the results and would recommendthe procedure to other persons. In patients with FSHD, bilateral STA provides satisfactory shoulder function with a high rate of scapulothoracic fusion and few or no significant respiratory repercussions.

About a new approach to calculating spiral clamps

The bearing capacity of spiral clamps, which are mounted on wires (cables) for their tension, connection, repair, etc., is studied. The design of spiral clamps is formed from stretched spirals that are wound onto conductors with an interference fit, which makes it possible to obtain tensile connections practically inseparable. The general problem of the interaction of spiral clamps and overhead line conductor layers is formulated. Different asymptotic solutions are given for initial and boundary value problems, and the design parameters of spiral clamps are determined to provide their carrying capacity. A wire layer is represented by the energy approach as an equivalent anisotropic elastic cylindrical shell, and wire construction as a whole is considered as a system of cylindrical shells inserted each other and interacting by forces of pressure and friction. The equivalence of the elastic properties of the shell to the properties of the wire layer is established using energy averaging. The constitutive relations obtained using the Castigliano theorem relate the generalized displacements and the corresponding forces. The matrix in these ratios is a stiffness matrix or flexibility matrix of a spiral wire structure. Such approach allows variety of interaction problems for spiral clamps with conductor layers to be solved, and the force transfer mechanism to be investigated from common positions. Static equations are written from the equilibrium of the elementary shell ring. It is considered that the length of the clamp is so great that the mutual influence of its ends can be neglected; the clamp is modeled as semi-infinite shell. This model allows the different initial and boundary value problems to be formulated, depending on the boundary conditions and clamp mounting methods on a conductor.

Optimization of wire construction from several 2G HTS tapes

Despite the second generation HTS tapes (2G HTS tape) have limits in critical current value, scientific and electric devices require more current density day after day. These requirements are realized by using different superconducting wires that consist of 2G HTS tapes designed in various combinations. Authors of this paper have developed the numerical model for estimation of total critical current in the superconducting wire and critical current in each 2G HTS tape placed in this superconducting wire. The current drop in six 2G HTS tapes having different constructions was analyzed. The result of this research is the decrease of critical current up to 25 % for the stack of tapes and up to 5 % for the parallel tapes in the same plane. In addition, what was also made is the estimation of the current distribution by length for six 25 m 2G HTS tapes in different constructions and determination of current deviation by length of the wire.

1894년 전라도 군용전신선 가설 계획과 일본 해군의 동학농민군 진압

1894년 전라도 군용전신선 가설 계획과 일본 해군의 동학농민군 진압